Ceramics such as silicon carbide or aluminum nitride have found widespread use, among other reasons because of their refractory nature; i.e. because they possess a high melting point. However, the refractory nature of ceramic material has heretofore precluded simple techniques for bonding of ceramic parts one to the other. Ceramic parts cannot simply be bonded by melting, because of the high temperatures required. Accordingly, prior approaches have typically employed low melting point organic epoxies. Unfortunately, low melting point epoxies negate the desired high melting point characteristic of refractory ceramic materials. Alternatively, such parts have been sintered in the presence of binders AND/OR lower melting glasses.
In an effort to provide high quality, reliable bonding of ceramics the art has employed other complex techniques. For example, U.S. Pat. No. 4,352,120 to Kurihara et al. entitled Semiconductor Device Using SiC As Supporter Of A Semiconductor Element discloses a method of bonding silicon carbide to silicon carbide by forming silicon dioxide on at least one of the surfaces to be bonded. A conductive layer, for example copper, is then evaporated on one silicon dioxide surface and the two surfaces are solder-bonded together.
Another technique for bonding silicon carbide parts is disclosed in U.S. Pat. No. 4,762,269 to Gyarmati et al. entitled Method Of Joining Molded Silicon Carbide Parts. A thin film containing at least one carbide and/or silicide forming element is applied to each surface to be bonded. The surfaces are then heated in an inert or reducing atmosphere under pressure. Other techniques of bonding ceramic materials have employed brazed metal alloy layers to form a bond between silicon carbide parts. See for example U.S. Pat. No. 4,602,731 to Dockus entitled Direct Liquid Pase Bonding Of Ceramics To Metals; and U.S. Pat. No. 4,784,313 to Godniemba-Maliszewski entitled Method For Bonding Silicon Carbide Molded Parts Together Or With Ceramic Or Metal Parts.
The above survey indicates that a simple and reliable method for bonding ceramic parts has heretofore not been available. Moreover, as ceramics and in particular silicon carbide find increasing use in the microelectronics industry, it would be desirable for a silicon carbide bonding technique to employ existing equipment and known process steps heretofore employed for semiconductor fabrication, but not for bonding of ceramics.